Had this earlier. A quick refresh fixed it, fortunately.I've also had to enter the code about a billion times in the past 3 months, but I've also purchased from several different computers in several different countries (sometimes the same computer in several countries) so that may be a cause. The code took about half an hour to come through once, making me fear I'd miss the 50% off on Frozen Synapse.

It was infuriating to not be able to buy, yet at the same time it may somewhat possibly sort of under the right circumstances prevent someone from logging into my account and buying a few hundred games with it (Steam and Amazon seem to be the only two places I store my CC info.) Of course, the odds of that seem lower than the odds of someone breaking into my Steam account also being able to break into my email...